Dear aspirant
At first lots of congratulations for your results .
I . According to trends of previous years and this year's JEE MAIN cut off I am afraid to inform you that your chances of getting admission into colleges NITs and IIITs are almost negative despite of OBC category. If it was ST or SC then there might be chance for you. One thing is very important that changes in OBC or those mentioned category seats depend upon those particular category rank not on All India rank.  You must mention your  OBC rank.However You can try in state level counselling and private colleges . Like

Amity School of Engineering, Noida

Amrita Vishwa Vidyapeetham, Coimbatore

Kalinga Institute of Industrial Technology, BhubaneswarBirla Institute of Technology, Mesra

Birla Institute of Technology and Science, Pilani

Walchand College of Engineering, Sangli

Vignan's Foundation for Science Technology and Research, GunturVel Tech Rangarajan Dr Sagunthala R and D Institute of Science and Technology, Chennai

https://engineering.careers360.com/articles/jee-main-cutoff-for-top-nits
check your chances here
https://engineering.careers360.com/jee-main-college-predictor?icn=QnA&ici=qna_answer

Best Wishes.